Impacts on sewer performance due to changes to inputs in domestic wastewater

摘要: The impacts of changes in domestic wastewater inputs on sewer performance have been debated since the dawn great construction movement 1850s. Nowadays, typical household that enters sewers can generally be divided into streams from WC, shower and/or bathtub, kitchen sink, washing machine and dishwasher. Changes composition entering a will depend inter alia properties appliances used households householders’ residential habits. Recent such with potentially detrimental impact are increased levels fat, oil grease practices; introduction sink food waste disposers; installation water efficient appliances. overall aim this thesis was, an historical perspective, to explore how recent systems relates as future carriers wastewater. Various methods examine employed. Two questionnaire surveys were distributed. first was sent out operators/managers employed at Scandinavian public utilities their views extent systems. second sewer/operators managers Northern Sweden monitoring incidents blockages. field studies also undertaken. One entailed investigation long term disposers housing areas. other evaluated which parameters could estimate infiltration/ inflow sewers. In addition, case analysis undertaken assess self-cleansing regimes networks when rural subarctic villages retrofitted A literature review performed identify analyse examining these may systems, implications for management. Responses survey suggested increase blockages due grease, particular pumping stations, most reported problem. indicated reoccurring blockage locations found low, although two possessed GIS-systems supported endeavours. study level in-sewer deposition observed pipe received high input effluents disposers. This further degree had gentle inclination combined significant sagging along its length. From it among compounds normally sampled determine characteristic, Tot-N Tot-P provided closest fit estimated infiltration/inflow based consumption rates. decrease in-pipe velocities all saving counteracted by relining rates did not drop below 130 l/hd.d. seemed dictated many factors, e.g. practices status separate pipes. Therefore there is need put context larger societal trends properly understand full regarding objectives relying carrier